The present invention relates to polymer coating application equipment and more particularly to components having a wear resistant coating formed thereupon.
Rotary paint atomizers (commonly referred to as xe2x80x9cbellsxe2x80x9d or xe2x80x9cpaint bell atomizersxe2x80x9d) are typically used for electrostatically applying fluids, such as polymer coatings, to many kinds of surfaces. Current technology uses paint bell atomizers composed of materials such as aluminum and high cost titanium. One problem with current paint bell atomizers is that they tend to wear out quickly (typically 5-7 weeks for paint bells used in automotive applications). When metallic, mica-based, or heavily pigmented coatings are used, the metal flakes, mica flakes, or abrasive pigments within the coatings tend to wear grooves into the surface of the bells. Such degraded paint bell atomizers may then apply coatings having an uneven or globbed appearance, which in turn require expensive and time-consuming defect removal and refinishing. In addition, it is relatively expensive to replace paint bells or paint bell components such as bell cups.
One possible solution to the wearing problem is to use harder metals, such as pure titanium, in the bells. Titanium paint bells typically last longer than bells. Titanium paint bells typically last longer than standard aluminum paint bells, but cost two or three times as much.
It is an object of the present invention to improve the durability of paint bells without significantly affecting the cost or performance of the equipment.
In accordance with the present invention, a silicon-doped (sometimes referred to as silicon-stabilized) amorphous carbon coating is applied to the wear surfaces, and specifically to the metallic bell cups, of metallic paint bell atomizers. Coated metallic bells have a significantly longer life than standard uncoated aluminum bells and have superior wear characteristics than standard uncoated titanium bells. In this regard, both aluminum and titanium bells have exhibited similar results with coatings applied.
The silicon-doped amorphous carbon coating has the further advantage of being relatively inexpensive to make and apply, especially when compared with the costs associated with replacing aluminum and titanium bell cups or with the cost of replacing an entire bell atomizer.
Other objects and advantages of the present invention will become apparent upon considering the following detailed description and appended claims, and upon reference to the accompanying drawings.